Allow Windows to use system Vsync if only one window is swapping

ui/gl/gl_context_egl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gl/gl_context_egl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "build/build_config.h"
@@ skipping 11 matching lines @@
 
 using ui::GetLastEGLErrorString;
 
 namespace gfx {
 
 GLContextEGL::GLContextEGL(GLShareGroup* share_group)
     : GLContextReal(share_group),
       context_(NULL),
       display_(NULL),
       config_(NULL),
-      unbind_fbo_on_makecurrent_(false) {
+      unbind_fbo_on_makecurrent_(false),
+      swap_interval_(1) {
 }
 
 bool GLContextEGL::Initialize(
     GLSurface* compatible_surface, GpuPreference gpu_preference) {
   DCHECK(compatible_surface);
   DCHECK(!context_);
 
   static const EGLint kContextAttributes[] = {
     EGL_CONTEXT_CLIENT_VERSION, 2,
     EGL_NONE
@@ skipping 75 matching lines @@
   SetCurrent(surface);
   if (!InitializeDynamicBindings()) {
     return false;
   }
 
   if (!surface->OnMakeCurrent(this)) {
     LOG(ERROR) << "Could not make current.";
     return false;
   }
 
+  surface->OnSetSwapInterval(swap_interval_);
+
   release_current.Cancel();
   return true;
 }
 
 void GLContextEGL::SetUnbindFboOnMakeCurrent() {
   unbind_fbo_on_makecurrent_ = true;
 }
 
 void GLContextEGL::ReleaseCurrent(GLSurface* surface) {
   if (!IsCurrent(surface))
@@ skipping 38 matching lines @@
   DCHECK(IsCurrent(NULL) && GLSurface::GetCurrent());
 
   // This is a surfaceless context. eglSwapInterval doesn't take any effect in
   // this case and will just return EGL_BAD_SURFACE.
   if (GLSurface::GetCurrent()->IsSurfaceless())
     return;
 
   if (!eglSwapInterval(display_, interval)) {
     LOG(ERROR) << "eglSwapInterval failed with error "
                << GetLastEGLErrorString();
+  } else {
+    swap_interval_ = interval;
+    GLSurface::GetCurrent()->OnSetSwapInterval(interval);
   }
 }
 
 std::string GLContextEGL::GetExtensions() {
   const char* extensions = eglQueryString(display_,
                                           EGL_EXTENSIONS);
   if (!extensions)
     return GLContext::GetExtensions();
 
   return GLContext::GetExtensions() + " " + extensions;
 }
 
 bool GLContextEGL::WasAllocatedUsingRobustnessExtension() {
   return GLSurfaceEGL::IsCreateContextRobustnessSupported();
 }
 
 GLContextEGL::~GLContextEGL() {
   Destroy();
 }
 
 #if !defined(OS_ANDROID)
 bool GLContextEGL::GetTotalGpuMemory(size_t* bytes) {
   DCHECK(bytes);
   *bytes = 0;
   return false;
 }
 #endif
 
 }  // namespace gfx